Alternating tourniquet system



Aug. 20, 1963 w. P. MURPHY, JR 3,101,085

ALTERNATING TOURNIQUET SYSTEM Filed June' s. 1961 RQ n; m

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rates 3,1b1,tl85 ALTERNATING TOURNl-'QUET SYSTEM William I. Murphy, Jr., `Miami, Fla., assigner to Cortlis Corporation, Miami, Fia., a corporation of Florida Filed .lune 8, 1961, Ser. No. 115,629 6 Claims. (El. 12S-325) nite This invention relates to blood flow limiting apparatus and more particularly to an alternating tourniquet system.

Certain types of heart lailments can `cause la condition known as pulmonary congestion in which an excess oi blood backs up in the patients lungs due to the inability of the left side of the heart to pump the entire volume of blood getting toit. This condition is immediately dangerous to the patient because the excess of blood lor fluid in the lungs prevents the normal exchange of air and therefore yoxygenation ofthe blood.

One simple way of treating this condition is to remove a portion of the patients blood. Another relatively simple and more useful technique is to trap and retain a portion of the patients blood in his extremities by means of tourniquets 4applied to the various limbs.

Another application of this technique is following lheart surgery or other direct injury to the heart. Removal of part of the blood load from the heart can speed its recovery and improve the patients overall ychances of recovery.

Preferably the tourniquets used in this technique are applied at the pressure which is yabove venous pressure but below arterial pressure. In this way, not only is the blood wlhioh was already in the limbs trapped there, but also additional blood from the body proper is allowed to enter the limb through the arteries causing a further dilation and pooling of blood, the venous return thereof being effectively blocked. However, pressure both above and below this range will also trap `a portion of the blood circulating and so should be understood to lie Within the scope of the present invention. must be reckoned with in selecting the proper pressures to be applied to the tourniquets is that the relative structure of the arm or leg will influence the value of pressure at wlhich maximum pooling is achieved. Thus typically a differentjpressure will be -applied to a patients arms than to bis legs.

In the application of tourniquets, it is recognized that if a tourniquet is left on any given limb for many hours that stasis may cause gangrene. It is therefore necessary that eaoh tourniquet be released periodically so as to permit a normal flow of blood completely through the limb. On the other hand, in the treatment of pulmonary congestion it is desirable that the volume of blood circulating, or conversely tbe 'amount of blood trapped, be kept substantially constant and that the heart not be subjected to any abrupt overloads. Accordingly, the tourniquets on the various limbs are released in rotation at periodic intervals. In that the volume 1of blood held by each arm is substantially less than that held by a leg, the two arms are typically treated as -a single unit to be released together, there then being three units to be rotated.

The type of tourniquet typically used is pneumatic, tbe structure being substantially similar to the type of inflatable tourniquet used in measuring blood pressure. Previously, the inflation and deflation of the several tounniquets required was accomplished by a nurse who bad to be in frequent or practically constant attendance and bad to exercise great care in order to perform each operation at the proper moment and in proper sequence.

Accordingly, objects of the present invention are to provide an alternating tourniquet system which will auto mati-cally inflate a plurality of pneumatic tourniquets in proper sequence and at proper intervals for the treatment of pulmonary congestion.

Another yfactor which arent 3,101,085 Patented Aug. 2i), 1963 quet inflations, wlhioh provide lair at a different pressure so that las fone valve is thrown from pressure to ex-V l for the Iarm tourniquets than for the leg tourniquets, which includes means for adjusting and measuring the various pressures applied to the tourniquets, simple and highly dependable in operation, and which is of relatively inexpensive construction. j e

For purposes of illustration a preferred embodiment of the invention is shown in the accompanying drawing in which: Y

FIGURE l isa diagrammatic illustration of an automatic alternating tourniquet system.

Referring now to the drawing there is provided la pump 10 `for supplying `air under pressure for iniiating the various pneumatic tourniquets. This pump is preferably electrically powered and is provided with leads 11 for connection to the standard alternating current mains. One of these leads contains a switch 12 so that the apparatus may be turned on or ott. For connection to the arm tourniquets 13 and the leg tourniquets 14 there are provided `outlets 21, 2.2 and 23 respectively which may be of any standard type. Each of these `outlets has associated with lit a two-position valve 31, 32 and 33, respectively, by which each `outlet may be connected to either the appropriate source of air .pressure or vented to the atmosphere. Each of these valves 31,- 32 and`33 are arranged to be operated by an A'associated cam follower 41, 42 and 43, respectively, and the cam followers in turn are driven by `a single timing cam 45. rfhe cam 45 is turned at a steady rate as for example two revolutions per hour by a geared-down synchronous electric motor 47 Which is, like the pump 10, arranged for connection to standard alternating current mains. The contour of the cam 45 is suoh that each valve 31-33 is, for two-thirds of the cams cycle, thrown so as to connect the 'corresponding tourniquet to its respective pressure source and 'for the remaining portion of the cycle, is thrown so as to permit the tourniquet to exhaust to the atmosphere. The cam followers 41-43 are equidistantly spaced `around the cam baust, an adjacent valve is lthrown from exhaust to pressure. The cam 45 is driven by the motor 47 through a friction clutch 46 so that the timing cycle may be reset by mmually rotating the cam 45 and thereby overriding the fclutch 46. For this purpose there is preferably provided a knob (not shown) connected directly to the cam 45 and projecting exteriorly of the apparatus.

Because of the difference in structure between arms and legs there are provided separate regulators l5 and 16 for regulating the flow of air to the respective tourniquets,

These regulators are preferably adjustable and there are provided gauges 17 `and 18 respectively by which the regulators may be adjusted to appropriate pressures. As explained above, these regulators are prefer-ably adjusted to pressures above venous and below arterial blood pressure but may also be set for pressures outside of this range.

Since in the treatment of pulmonary congestion it is necessary to take blood pressure measurements frequently, there is provided in the preferred embodiment shown means for utilizing the gauge 17 for this purpose. A three-way valve 35 is |arranged so that at least one of the arm tourniquets may be connected either to the full pump pressure or permitted to exhaust to the atmosphere through a needle valve 37 as well as bein-g connected to its associated programmed source of -air pressure. By means of this valve 35 a physician may iirst inlate the corresponding `arm tourniquet to a pressure above arterial and then slowly release that pressure through the adjustable needle valve 37. By listenin-g for arterial sounds at the anticubital space the physician may then determine at what pressure arterial blood again begins to flow. By this means blood pressure may be taken `and the arm returned to its blood storing function Without disturbing the existing tourniquet arrangement.

It should be understood Vthat this disclosure is for the purpose of illustration only `and that the present invention inclu-desI all moditications and equivalen-ts falling Within the scope of the appended claims.

I claim:

l; An alternating tourniquet system comprising: a source of air pressure; a pair of pneumatic arm tourniquets; a 'first pneumatic leg .tourniquetg a second pneumatic leg tou-rniquet; valve'mea'ns having a rst state in which Vthe arm -tourniquets and( the-iirst of the leg tourniquets l further Vcomprising means for regulating the air pressure available from said source to a pressure which is above venous but below arterial pressure.

v3. An alternating tourniquet pressure controller comprising a source of air pressure, first regulating means for adjusting air pressure to a level suitable for application to pneumatic arm tourniquets, a second regulating means for adjusting Iair pressure to a level suitable Vfor application to pneumatic leg tourniquets, Va first outlet, a second outlet, a third outlet, said iirst outlet being connectable only to said first regulating means and said second and third 'outlets being -connectable only to said second regulating means, valve means for selectively connecting any Y. nectedhto the pump lfor providing air pressure suitable for application to said leg tourniquets; valve means having `a iirst state in which the tourniquets Vand theV tirstof the leg tourniquets are subjected to respectively appropriate pressures, 'la second state in which both leg tourniquets are subjected to an appropriate pressure and a third state in which the arm toumiquets and said second leg tourniquet are subjected to respectively appropriate pressures; and moto-r means for driving said valve means successively from one state to the next in rotation at a predetermined rate. v

5. An alternating tourniquet system according to claim 4 including a pressure gauge associated with each of said pressure regulating means.

6, An alternating tourniquet system according to claim 5 including manually controllable means for selectively applying pressure directly from the pump to the arm tourniquets and then gradually venting the arm tourniquets to the atmosphere independently of the state of said valve means thereby facilitating the measurement kof blood pressure.

Reterences Cited in the tile of this patent UNiTED STATES PATENTS 

1. AN ALTERNATING TOURNIQUET SYSTEM COMPRISING: A SOURCE OF AIR PRESSURE; A PAIR OF PNEUMATIC ARM TOURNIQUETS; A FIRST PNEUMATIC LEG TOURNIQUET; A SECOND PNUEMATIC LEG TOURNIQUET; VALVE MEANS HAVING A FIRST STATE IN WHICH THE ARM TOURNIQUETS AND THE FIRST OF THE LEG TOURNIQUETS ARE CONNECTED TO SAID SOURCE AND SAID SECOND LEG TOURNIQUET IS VENTED TO THE ATMOSPHERE, A SECOND STATE IN WHICH BOTH LEG TOURNIQUETS ARE CONNECTED TO SAID SOURCE AND THE ARM TOURNIQUETS ARE VENTED, AND A THIRD STATE IN WHICH THE ARM TOURNIQUETS AND SAID SECOND LEG TOURNIQUET ARE CONNECTED TO SAID SOURCE AND SAID FIRST LEG TOURNIQUET IS VENTED; AND MOTOR MEANS FOR DRIVING SAID VALVE MEANS SUCCESSIVELY FROM ONE STATE TO ANOTHER IN ROTATION AT A PREDETERMINED RATE. 